After heavy rains, debris flows hit Southern California community scarred by fire

Mudslides and landslides have hit areas of California that were recently devastated by the worst fires in the states' history.

Residents of a Southern California mountain community near the Eaton Fire burn scar were left digging out of roads submerged in sludge after the strongest storm of the year swept through the area.

The storm unleashed flows of debris and left some people trapped in the mud.

Water, debris and boulders rushed down the mountain in the city of Sierra Madre on Thursday night local time, trapping at least one car in the mud and damaging several home garages with mud and debris.

Bulldozers were cleaning up the mud-covered streets in the city of 10,000 people the following day.

"It happened very quickly but it was very loud and you could even hear the ground or feel the ground shaking," said Bull Duvall, who has lived in Sierra Madre for 28 years.

Sierra Madre officials issued evacuation orders for areas affected by the Eaton Fire, warning that fire, police and public works personnel would not enter areas experiencing active mud and debris flows.

Officials added that anyone who remained in a home under evacuation orders would need to shelter in place until areas are deemed safe for city personnel to enter.

Residents of the city also had to evacuate during the Eaton Fire, which destroyed 15 homes in the community.

In nearby Altadena, a road near the burn scar was also covered in several feet of mud, vegetation and trees as a flood of water overcame concrete blocks put in place to prevent this from happening.

Luckily, the area was mostly deserted.

In Pacific Palisades, one highway intersection was submerged in about 1 metre of sludge, with some drivers trying to force their way through and police officers pushing one vehicle through the muck.

Bulldozers worked to clear the roads not far from where, just weeks ago, they moved abandoned cars after people fleeing last month's wildfires got stuck in traffic and fled on foot.

One member of the Los Angeles Fire Department was stuck in a vehicle when it went into the water in Malibu and was able to exit with minor injuries, department spokesperson Erik Scott said.

On Friday morning, Scott posted a video on social media showing crews clearing a mud-coated stretch of the Pacific Coast Highway in Malibu.

Southern California reported 2.5 to 7 centimetres of rain in coastal areas and valleys and 7.6 to 15.2 centimetres across the coastal slopes on Thursday, said Mike Wofford, a meteorologist with the National Weather Service.

The risk of rock and mudslides on wildfire-scarred hillsides continues as dangerous slides can strike even after rain stops, particularly in scorched areas where vegetation that helps keep soil anchored has burned away.

But despite recent storms, much of Southern California remains in extreme or severe drought, according to the US Drought Monitor.

Daniel Swain, a climate scientist at the University of California, Los Angeles, said that while the area is desperate for rain, this storm might bring too much too quickly.